The bridge and an adjacent section of Porchester Road will be closed to northbound traffic from 27 October to 7 December in order to remove the two water mains that cross Lord Hill’s Bridge
To carry out this work they will need to excavate above the two water mains and then reinstate the road once the pipe is sealed off. This work was completed on the north side of the bridge and now needs to be carried out on the south side. Alternative routes will be signposted over Westbourne Bridge to the east and Great Western Road to the west. This work is expected to be complete within six weeks and access to Royal Oak station will be maintained throughout the works. The footway width will be reduced, but Crossrail will maintain a pedestrian route to the station at all times.
Please see this PDF from Crossrail for more details